The present invention relates to the field of domestic implements usable by households for convenience and more particularly to an electric generating domestic implement for providing auxiliary alternating current electric energy for household and other domestic use.
The invention is directed to an electric generator implement powered by a standard lawn mower. Thomas U.S. Pat. No. 4,446,679 shows a standard lawn mower driving a tiller or snow blower. An arrangement for strapping a standard lawn mower onto the top of an implement being driven by the lawn mower is disclosed. For this reason, and as general background information, this patent is incorporated by reference. In a like manner, Middleton U.S. Pat. No. 4,597,203 is incorporated by reference herein as background information.
In recent times, there has been an increased demand for domestic electric generators to provide alternating current for lighting, cooking and appliances, especially during interruptions in normal electric circuits. Also, there is a demand for portable generators to provide electrical service in diverse locations around the home. A large variety of domestic generators are on the market. Such units use gasoline engines to drive electrical generators that provide 110 VAC and possibly 220 VAC. Such domestic electric generators are very seldom used; therefore, the units are relatively expensive when compared to the actual time they are used. Such household generators include gasoline engines, thus adding drastically to their bulkiness, weight, cost and storability. Consequently, there is a market need for a domestic or household electric generator implement that is low cost, requires very little storage space and does not present difficulty associated with storing gasoline driven implements.
The present invention is directed toward a domestic implement for providing a source of alternating current to be used during periods of power interruption, or in remote areas not serviced by electric power. The domestic implement contemplated by the present invention is an energy source powered by a standard gasoline driven lawn mower. The lawn mower, in accordance with the invention, is not modified. The use on an unmodified standard gasoline driven lawn mower to drive a domestic electric generator provides two distinct domestic implements at a lower cost, reduced storage space, and easier storability.
In accordance with the present invention, there is provided a portable implement that can be easily moved and generates electric energy for domestic use. This implement includes an electric generator having a drive shaft rotatable about a shaft axis and at least one set of electrical output leads for AC current. A support housing of the implement includes a lower ground engaging base, an upper support plate with a central access opening, a bracket in the housing to mount the generator with the generator shaft axis extending generally vertically up through the access opening and a platform on the housing to fixedly attach a standard gasoline driven lawn mower with a cutter blade rotatable about a blade axis. In this manner, the lawn mower is mounted on the housing with the blade axis extending generally parallel to, and generally aligned with, the shaft axis. A universal shaft coupling allowing misalignment of the two axes is carried by the generator drive shaft and extends upwardly through the access opening. The coupling of the invention has two sections. The lower section is connected to the drive shaft of the generator for rotating the shaft about its axis and the upper section includes an upwardly facing nest that receives the cutter blade for rotation of the upper section by the cutter blade about the blade axis. The universal coupling allows rotation of the blade about one axis to drive the generator about another axis. Ideally, the two axes coincide; however, practically they do not. They are laterally offset. Thus, it is necessary to provide a universal joint having at least orthogonal relative movement. In the preferred embodiment, an oldham coupling is employed whereby spaced glidable members allow rotation of one section about one axis and a second section about another axis.
In accordance with another aspect of the invention, the cowling about the lawn mower is gripped by at least four engaging bumpers that center the lawn mower blade over the generator shaft. These bumpers are adjustable in a transverse direction to accommodate a variety of domestic lawn mowers. After the bumpers are adjusted for a particular lawn mower, they are locked in position. The mower is automatically centered on the housing of the implement by merely centering the cowling with the previously fixed, upstanding adjustable bumpers.
In accordance with another aspect of the present invention, the universal joint has an upper section that is spring biased from the lower section. As the lawn mower is mounted on the housing of the implement, the standard blade of the lawn mower pushes the top section of the coupling toward the bottom section or lower section of the coupling. By rotating the blade with respect to the generator, the blade ultimately drops into the nest at the top of the upper section. This nest preferably involves an elongated slot for capturing the lawn mower blade. However, two orthogonal slots could be provided in the upper section of the coupling. As an alternative, upstanding abutment elements can be provided. In accordance with one aspect of the invention, the abutment elements are tapered pins. When the lawn mower is placed over the housing of the generating implement, the blade automatically centers on the coupling for driving the coupling to, in turn, drive the generator. In this alternative embodiment of the invention, the upper section of the coupling need not be spring biased.
In accordance with another aspect of the present invention there is provided a method of driving an electric generator by its drive shaft. The generator has an upstanding coupling with an upper section provided with at least one diametrically extending blade receiving slot. This upper section is spring biased away from the lower section of the coupling in a direction of the generator drive shaft. The method involves a standard lawn mower of the type having a lower cutter blade driven by a gasoline engine. Such lawn mower is started by a pull cord when a manually operated start switch is closed. The method involves setting a lawn mower on the generator with the cutter blade engaging and pushing the upper section downward and, then, pulling the pull cord at least once while the start switch is opened so the blade drops into the slot. Thereafter, the start switch is closed and the cord is pulled to start the engine for driving the generator.
The primary object of the present invention is the provision of a portable domestic generator driven by a standard lawn mower without modifications to the mower.
Yet another object of the present invention is the provision of a portable domestic generator, as defined above, which is inexpensive, can be stored in a small space and need not involve the storage of a gasoline driven engine.
Still a further object of the present invention is the provision of a portable domestic generator, as defined above, which generator accommodates a wide variety of domestic lawn mowers.
These and other objects and advantages will become apparent from the following description taken together with the accompanying drawings.